diff --git a/parse_powerisa_pdf/parse_powerisa_pdf.py b/parse_powerisa_pdf/parse_powerisa_pdf.py
index a4afd09..409c6ac 100755
--- a/parse_powerisa_pdf/parse_powerisa_pdf.py
+++ b/parse_powerisa_pdf/parse_powerisa_pdf.py
@@ -1503,7 +1503,7 @@ class Parser:
                 f"instruction bit fields box has wrong number of horizontal lines:\n{h_lines}")
         if len(v_lines) < 2:
             raise InsnParseError(
-                f"instruction bit fields box has too few vertical lines:\n{h_lines}")
+                f"instruction bit fields box has too few vertical lines:\n{v_lines}")
         bottom_line, top_line = h_lines
         box_min_x = v_lines[0].x0
         box_max_x = v_lines[-1].x0